Continuing development of a computer system (SAAM) for the simulation, analysis, and modeling of bio-kinetic systems. Further development of a conversational mode of operation increased the versatility, applications and automated the modeling process. The programs which make up SAAM have been revised so that they can run on a DEC-20 computer system and IBM series 370 computer systems, thus making SAAM available to a wider range of users. Application of the SAAM program in the development of compartmental models for the metabolism of chylomicrons in rats. Using the model it was determined that chylomicrons of all sizes are taken up as intact lipoprotein particles and that in rats a major portion of the fatty acids taken up by the liver are in the form of triglycerides before hydrolysis. The development of a compartmental model for the solution species of Bovine lipoprotein lipase resulted in the prediction of an active tetrameric species and an inactive oligomaric species. This provides the first explanation of the loss of activity upon standing at room temperature. Further analysis of lipoprotein metabolism indicates that the apoB/E receptor plays a major role in apoB-100 metabolism but does not affect the apoB-48 metabolism. In addition the apoE phenotype in humans is a determinant in the kinetics of low density lipoprotein metabolism through the apoB/E receptor.